Author Contributions: Dr Staiger had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Staiger, Auerbach, Buerhaus.
Acquisition of data: Staiger, Auerbach.
Analysis and interpretation of data: Staiger, Auerbach, Buerhaus.
Drafting of the manuscript: Staiger, Auerbach, Buerhaus.
Critical revision of the manuscript for important intellectual content: Auerbach, Buerhaus.
Statistical analysis: Staiger, Auerbach.
Administrative, technical, or material support: Staiger, Buerhaus.
Study supervision: Buerhaus.
Financial Disclosures: None reported.
Funding/Support: This work was supported by grant 2 P01 AG19783-06 from the National Institute on Aging (Dr Staiger).
Role of the Sponsor: The National Institute on Aging played no role in the design and conduct of the study, in the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Disclaimer: The views expressed in this article are those of the authors and should not be interpreted as those of the US Congressional Budget Office.